In the past, since a glass container is excellent in recyclability and storage stability for contents and has weight and unique texture not provided in a plastic container, a glass container has been widely used as a container that stores cosmetics, perfume, or the like.
Further, containers that store cosmetics, perfume, and the like require functionality and the beauty and classiness of appearance based on an excellent design in terms of inducing customers to buy.
Furthermore, a glass container, which includes a bubble formed in a bottom portion, is proposed as one of glass containers having excellent designs and classiness, and is highly evaluated as a container having a unique design effect.
However, since the position and size of a bubble need to be appropriately and finely adjusted in the manufacture of a glass container that includes a bubble in a bottom portion, the glass container is generally manufactured by semi-manual steps that are performed by artisans. For this reason, there is a problem that it is difficult to mass-produce glass containers.
Accordingly, a method of industrially mass-manufacturing a glass container, which includes a bubble formed in a bottom portion, by an automatic molding machine is proposed (for example, see Patent Documents 1 and 2).
That is, Patent Document 1 discloses a method of manufacturing a glass container. As illustrated in FIG. 10, the method of manufacturing a glass container includes: a step of pushing a predetermined amount of air to molten glass 705 present in an orifice 704 of a gob feeder 701 from a tip portion of a plunger 702, which vertically reciprocates to continuously extrude molten glass 705 from the orifice 704; a step of extruding the molten glass 705 from the orifice 704 by the plunger 702 as the molten glass 705 including an air bubble 709; a step of cutting glass gob 712 by a shearing mechanism 711 and supplying the glass gob 712 to a molding machine; and a step of molding bubble-including glass container by a press molding method or a press-and-blow molding method.
Further, Patent Document 2 discloses a method of manufacturing a glass container that includes a bubble put in a bottom portion. As illustrated in FIG. 11, the method of manufacturing a glass container includes: a step of forming a dent on a parison 805 or the bottom face of a glass container 812, which obtained immediately after blow molding, by a pin 810 provided in a mold 807 for molding the bottom portion of a glass container 812; and a step of forming a bubble 814 by blowing air into the dent.